On Mon, 29 Feb 2016, John Willis wrote:
FWIW, the IBM term for "motherboard" was
"planar", at least in the era
of the PC, PC/XT, PC/AT, etc. The first computer to which I had access
was my father's 5150 in approximately 1984; I remember the machine came
with dual floppy drives and a 64K system planar with an Intel 8088. At
some point, a technician came out and put in a different planar with
256K on-board, added an additional 256K via expansion board, and
configured it with a 30MB half-height Winchester drive and controller.
This second planar had an AMD D8088 at the same 4.77MHz speed as the
Having this machine handed down to me in about 1991 sparked my interest
in programming; many hours of BASICA silliness and PC-DOS batch file
IBM also, at that time, sometimes called it, "System Board".
When IBM announced the 5150 in August 1981, I tried to get my uncle, who
worked for IBM, to get me the "employee family discount". He refused.
So, I was delayed a couple of months in ordering one.
I bought, retail at Compurland: system unit, Floppy disk controller, CGA
video board, Async (RS232 & 20ma), parallel printer board, and PC-DOS
1.00. (RAM, floppy drives, composite monitor were all commodity items
that I had for TRS80s, and readily available at less than 20% of IBM's
My uncle (a generally unreliable source) said that the reason that IBM
didn't call it, "motherboard" was that that was "street slang",
specifically mentioning TV broadcasts of Black Panther speeches at
Merritt College in the late 1960s (when I was playing with 1620 and 1401
there!). The speeches had very frequent use of the word "motherfucker",
which of course was changed to "mother[bleep]" or "mother" by the TV
people. I do not think that the Black Panthers ever used the word "Planar".
(There was a New Yorker cartoon of a biddy watching TV saying to her
friend, "I just love the way that he says 'Mother'." I'd love to
cartoon of a Panther speaker saying, "Up against the wall, Planar_!")
Grumpy Ol' Fred cisin at xenosoft.com